Heat-treating apparatus



May 9, 1944. K. L sco'fr i HEAT TREATING APPARATUS Filed Dec. 13, 1941 /Nvvran A. L .Scarf 8%7? Aff Afrox/vir Patented May 9,

- UNITED STATES 42,348,501 PATENT OFFICE HEAT-TREATING APPARATUS Kenneth L. Scott, WesternSpr'ings, lll., assigner to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application December-13, 1941, Serial No. 422,783 4 claims. (ol. zes- 5) This invention relates to a heat treating apparatus and more particularly to an apparatus for heat treating' metals.

In the heat treatment of some types of magnets, it is necessary to control the rate of cooling within a limited range in order to produce the de-v sired magnetic properties. One method of cooling has been to place the heated magnets in an insulated chamber. However, in this method, the

initial cooling of the heated magnets occurs at a very rapid rate because of the absorption of g heat by the insulation when it is first exposed to 'Fig'. l a side elevation of one embodiment of the invention,

Fig. 2 is a' plan view of the same, Fig. 3 Ais an end elevation of the saine. In one method employed in the manufacture of magnets composed of iron, nickel, aluminum, cobalt and copper, it is necessary to heat the magnets to a temperature of about 2100 Fahrenheit.

Then, in order to produce the desired magnetic qualities, it is necessary to cool the magnets at a substantially uniform rate. Satisfactory results,`

have been obtained where the magnets have been permitted to cool to 1100" Fahrenheit. in approximinutes. In order to achieve a uniform vrate of cooling, numerous methods have been employed heretofore with varying success.

'In onemethod, the magnets were placed in an insulated chamber.- However, a sudden initial dropin temperature is caused by the absorption ofheatbytheinsulatlonand them-astheinsulation becomes warm, the rate oi' cooling becomes quite slow. This extreme variation inthe rate of cooling is imdesirable. .In another method.

coolinghas been thermostaticallyoontrolled by .I

placingthe magnetsinathermcstaticallyconftrolbdoven. Thismethod, however. isexpensi've.

To overcome these dimculties, in-accordance with this invention, achamberis employed having aheatreilectinglinlnzwhichwillntiliaetheheat `radiatedblythearticlestollecooledtoretardcoolingandtoeilectauniformra'teofcoolins.

AA. reeetor material was required which would behizhlyeilicientwhildatthesametimdrelativelyinertto the etlectoftbeheatradiated by the Anodiled'ahnnimnnissuchamaterial. Anodizirmthealuminumgiveaareiiector suryfacewhichiseiiicientsndatthes'ametime, .o

durable. Tests have shown that untreated aluminum rapidly oxidizes when exposed to the heat of the magnets and this oxidation causes a discoloration of thesurface of the aluminum with resultant loss of reector emciency. The an- 5 odized aluminum, on the other hand, does not discolor and maintains its eiiiciency over 'd long period of use.

Referring now in detail to the construction shown in Figs. l to 3 inclusive, the heat treating lo chamber comprises a removable cover il of anodized sheet aluminum of suitable thickness. A handle Il has been provided for convenience in removing the cover Il. 4A base I2 comprises a sheet of anodized aluminum and the cover Il is simply placed cn the base I2. Also resting on the bas I2 is a removable rack Il supported by six posts I3 of suitable material. A removable tray I5, which is formed of an open mesh material and contains magnets i6, is supported by the rack Il. Open mesh, metallic material is used in the tray to increase the area of eiIective radiation of the objects supported thereby.

In the operation of this embodiment of the invention, the tray containing thefmagnets is removed from the furnace, whereinthe magnets have been heated to the required temperature. The tray is then placed on the rack which rests on the base plate, as shown inFigs. 1 and 3, and

the cover is placed over the tray and rests on l the base plate. Thus, the magnets are completely surrounded by walls of anodized aluminum and very eil'ective reflection of the heat radiated by the magnets is achieved. The result is that the magnets cool at a uniform rate. The speed of cooling approximates the optimum rate but if necessary the cover ma! be removed from time to time to increase the rate of cooling. l

It will be understood that the nature and em- 40' bodiment of the invention herein described is merely illustrative and that many changs and modiiications may be made therein mthout departing fromthespirlt andscopeoftheinm What is claimed is:

4o 1. In an apparatus for heat treatintarticles.

a lining of anodized almninum for controllingtbe cooling rate of the articles therein.

2. In an'apparatus for heat treating articles. meansfor reflectinxheatradiatedbythearticles 5d. therein comprising a lining of anodized alumi- Bum.

3. Inanapparatususedintbeheattreatment of magnetic articles. means for providing esubstantiall'yimiformrateofcoolingbyreecting heat radiated by the articles aliningotanodiledalmninum.'

4.Anapparatusforheattrectingarticlescomprising a chamber havinsasurfpofanndind aluminunrfor heattotheartick mism. 

